Unlike wired links, wireless links have high error rates and thus require the technique of processing a wireless link signal in an error-robust manner. Also, since packet transmission resources are limited, the wireless links may reduce a resource loss through a header compression technique. Examples of the header compression technique include a robust header compression (ROHC) technique.
In an ROHC technique, a transmitting end transmits only changeable information among the information included in a header to a receiving end on the basis of the context of configuring a packet dynamically during transmission for header compression. The receiving end may restore the compressed header on the basis of the context information.
A mobile station (MS) may change an access service network gateway (ASN-GW) through a handover. Hereinafter, a handover changing an ASN-GW of an MS will be referred to as an inter ASN-GW handover.
In an inter ASN-GW handover, a serving ASN-GW transmits the context information and the ROHC parameter of an MS to a target ASN-GW by means of ROHC such that the target ASN-GW and the MS may communicate traffic data therebetween.
As described above, the serving ASN-GW transmits the context information and the ROHC parameter to the target ASN-GW in the inter ASN-GW handover of the MS.
If the serving ASN-GW and the target ASN-GW have different ROHC capabilities, they may use different ROHC parameters. Accordingly, the target ASN-GW may fail to perform the ROHC with the MS by means of the ROHC parameter received from the serving ASN-GW.
Also, the serving ASN-GW requires many resources to transmit the context information. Accordingly, in the inter ASN-GW handover of the MS, the serving ASN-GW may fail to transmit the context information to the target ASN-GW in an IP packet format together with other information.